The present invention relates to a disc player such as a single disc player, or a carousel-type disc player capable of playing a selected one of a plurality of discs. More particularly, the invention relates to a loading-type disc player having a slide base holding discs thereon and movable back and forth for transferring the discs between an exchange position and a store position.
Conventional disc players include a carousel type player having a rotatable tray for carrying a plurality of medium discs such as CD, DVD, and the like, a desired one of these discs being selected and played.
Japanese Patent Application Laid-Open Publication No. 5-182335, for example, discloses one such multi-disc player. The multi-disc player disclosed in this publication includes a slide base or tray base on which a plurality of discs are carried, wherein forward and backward movements of the slide base are effected through a planetary gear mechanism in combination with a rack and a substantially U-shaped toothed gear having connecting tooth, for enabling discs to be exchanged even during the play of a disc.
That is, a single motor is used for selectively driving the slide base and performing a clamping operation of a disc by means of the planetary gear mechanism. For driving the rotary tray mounted on the slide base, another motor is provided.
However, the multi-disc player disclosed in the abovementioned Japanese Patent Laid-Open Publication No. 5-182335 has the problem of high cost, i.e., since a locking mechanism for locking the slide base extending from a casing during an exchange of discs must be additionally provided, the number of components is increased and the cost for the player as a whole is high.
In other words, a disc player is normally provided with a built-in push-close mechanism for automatically withdrawing the slide base upon detection of pressure on the slide base towards the casing. Therefore, if discs are to be exchanged during another disc is being played, for instance, the slide base must be locked in its fully extended position so that the push-close mechanism will not be operated, because, otherwise, the playing device and the others may be damaged. Thus an additional locking mechanism for achieving this had to be provided.
The present invention has been devised for solving the problems described above, and an object of the present invention is to provide a disc player which is manufactured at low cost due to a reduced number of parts.
To accomplish the above-mentioned object, according to a first aspect of the present invention, there is provided a disc player comprising a chassis, a slide base supported on the chassis so as to be movable in forward and backward directions between a disc exchange position and a disc store position, the slide base capable of holding a disc as a recording medium thereon, a clamp mechanism for clamping a disc to be played at a disc play position, and a planetary gear mechanism for selectively causing the movement of the slide base in forward and backward directions and a clamping operation by the clamp mechanism with a single drive source. The planetary gear mechanism includes a sun gear rotatably mounted on the chassis and driven by the drive source, a planetary gear rotated by a drive force transmitted from the sun gear, and a rotary member provided with the planetary gear and mounted on the chassis such as to be rotatable around a center axis of the sun gear.
Then, a linear rack gear is formed on a bottom face of the slide base, and the slide base is moved in forward and backward directions by rotation of the planetary gear in engagement with the linear rack gear. Further, a first arcuate rack gear is formed in the chassis at a position so that it locates adjacent the linear rack gear when the slide base is located at the disc store position so as to allow the planetary gear to engage therewith consecutively from the linear rack gear, and a clamping operation of a disc by the clamp mechanism is performed by a revolving movement of the planetary gear in engagement with the first arcuate rack gear.
According to a second aspect of the present invention based on the first aspect described above, the clamp mechanism comprises a float base, one side of which is rotatably mounted on the chassis, and a clamp cam for causing the float base to move upwards and downwards. The clamp cam is moved by revolving the rotary member having the planetary gear in engagement with the first arcuate rack gear by a drive force from the drive source for moving the float base to move upwards and downwards to perform a disc clamping operation and a disc releasing operation.
As an effect according to the first and second aspects of the present invention, the first arcuate rack gear is formed in the chassis, and when the slide base is at its disc store position, clamping of a disc is accomplished by revolving the planetary gear in engagement with this first arcuate rack gear. That is, because the planetary gear toothes with the first arcuate rack gear, which is integrally formed in the chassis, reaction forces generated during the clamping operation are received by the chassis, whereby the clamping operation is performed stably.
In addition, according to a third aspect of the present invention based on the first or second aspect described above, a second arcuate rack gear is formed continuously with the linear rack gear on the bottom face of the slide base, and a linear cam groove is formed on the bottom face of the slide base parallel to the linear rack gear. The rotary member has a lock pin which is engaged with and guided by the linear cam groove during the slide base is moving. Further, an arcuate lock cam groove is formed continuously with the linear cam groove on the bottom face of the slide base. The second arcuate rack gear and the arcuate lock cam groove have respective radius centers conforming to the center axis of the sun gear when the slide base is located at the disc exchange position. After the slide base has reached the disc exchange position, a further rotation of the sun gear causes the rotary member to revolve, with the planetary gear being engaged with the second arcuate rack gear, while the lock pin of the rotary member is in engagement with the arcuate lock cam groove for locking the slide base not to move in forward and backward directions.
According, then, to a fourth aspect of the present invention based on the third aspect described above, the slide base supports a rotary tray which is capable of carrying a plurality of discs thereon, the rotary tray being rotated by a drive mechanism and positioned at a location for playing a selected one of the plurality of discs. The linear rack gear includes a first linear rack gear continuing from one end of the first arcuate rack gear and a second linear rack gear continuing from the other end of the first arcuate rack gear. The slide base is moved by engagement of the planetary gear with either one of the first linear rack gear or the second linear rack gear during a clamping operation being performed by the clamp mechanism, whereas the slide base is moved by engagement of the planetary gear with the other one of the linear rack gear and the second linear rack gear during an unclamping operation being performed by the clamp mechanism. Further, the second arcuate rack gear is continuously formed with the other of the first linear rack gear or the second linear rack gear.
Also, according to a fifth aspect of the present invention based on the fourth aspect described above, the first linear rack gear comes to a position adjacent one end of the first arcuate rack gear continuously therewith, while the second linear rack gear comes to a position adjacent the other end of the first arcuate rack gear continuously therewith, when the slide base is located at the disc store position.
As an effect according to the third to fifth aspects of the present invention, the second arcuate rack gear and the arcuate lock cam groove are formed such that their radius center conforms to the axis of the sun gear when the slide base is at is disc exchange position. The planetary gear is toothed with the second arcuate rack gear, while the lock pin is engaged with the arcuate lock cam groove by revolving the rotary member, for locking the slide base not to move back and forth. Therefore, additional parts for locking a push-close mechanism which must be stopped during the play of a disc are not necessary. A reduction in cost is achieved by the reduction in the number of components.
In addition, according to a sixth aspect of the present invention based on any of the third to fifth aspects described above, the lock pin is provided on the rotary member at a position circumferentially offset at 45 degrees with respect to the planetary gear.
Then, according to a seventh aspect of the present invention based on any of the third to sixth aspects described above, the arcuate cam groove formed continuously with the linear cam groove has a curved portion in a deformed U shape bulging outwards from the linear cam groove.
As an effect according to the sixth and seventh aspects of the present invention, the lock pin for locking the slide base in the forward and backward directions is mounted on the rotary member at a circumferentially offset position at 45 degrees with respect to the planetary gear. Therefore, the planetary gear and the lock pin will not be aligned in a straight line while the slide base is moving, whereby the planetary gear is toothed with the rack gear without too much play, enabling the slide base to move smoothly.